Hemimastix

Hemimastix Foissner, Blatterer & Foissner, 1988 (ref. ID; 5727)

[ref. ID; 5727]
Diagnosis; Small (less than 20 um), conspicuously flattened Spironemidae with kineties in distinct furrows and extending to posterior end. Cortex rigid, extremely plicate and with distinct flagellar ridge; cells ametabolic and acontractile. (ref. ID; 5727)
Remarks; Differs from Spironema and Stereonema by the highly plicate, rigid cortex, the continuous flagellar groove ("distinct furrow") and the flagellar ridge, which is a bulge around and between the flagellar bases. It can be clearly distinguished from Spironema by the absence of euglenoid movement. (ref. ID; 5727)
Type species; Hemimastix amphikineta Foissner et al., 1988 (ref. ID; 5727)

Hemimastix amphikineta Foissner, Blatterer & Foissner, 1988 (ref. ID; 5727) reported author and year? (ref. ID; 4898)

Hemimastix amphikineta Foissner, Blatterer & Foissner, 1988 (ref. ID; 5727) reported author and year? (ref. ID; 4898)

Diagnosis

In vivo 14-20x7-10 um. Body ellipsoid, about 2:1 flattened. Capitulum conspicuous kineties with about 12 flagella each. Nucleus roundish. (ref. ID; 5727)

Descriptions

Light microscopy: Shape remarkably constant, ellipsoidal both from short and broad axis view; posterior end slightly tapered, anterior end transverse truncate by distinct capitulum. Nucleus subequatorial. Contractile vacuole at posterior end, surrounded by bleb-like vesicles. Extrusomes not recognizable in light microscope. Flagella 5-9 um long, rigid, beat asynchronously. Food vacuoles 1-5 um in diametre, contain remnants of bacteria and heterotrophic flagellates. Cytoplasm with refractile granules (0.3-1.5 um) often liearly arranged. Movement trembling, creeping among detritus, cannot swim. (ref. ID; 5727)
Electron microscopy: Cortex highly plicate, flagellar furrow pipartite, i.e. consisting of amicrotubule and a naked furrow. Epiplasm with electron-dense sheet, continuous nearly up to posterior end; epiplasm-free region confined to microtubule furrow. Distinct ridge between and around flagella. Extrusomes anchored in and near capitulum. Anterior compartment with thick granular centre, tip cup-like, posterior end ("nail head") with three granule-like thickenings. Posterior extrusome compartment with single anterior bulbous dilation. (ref. ID; 5727)

Type location

Upper soil layer (0-3 cm) of a bushland in Brisbane-Waters National Park, near Sydney, East Australia, 151 degrees E, 34 degrees S. (ref. ID; 5727)

Occurrence and ecology

Discovered in several terrestrial biotopes from Australia and Chile (sandy and humic soils, bark of trees). Later we found it in soils and bromeliad mud from Costa Rica, in a soil sample from Gough Island, Antarctica, and in the bark of an Ohia tree in Hawaii. Hemimastix amphikineta is as yet found only south of the tropic, i.e. occurring mainly in the southern hemisphere like some other protists (Foissner 1987). Zolffel (pers. commun.) claims to have found it is a forest litter in Berlin, Germany. However, he may have confused the Berlin samples with a sample we sent him from the type location. All these soil samples were air-dried for at least 20 days. Some of them, e.g. the bark of an Ohia tree in Hawaii appeared completely dry when collected. It is thus reasonable to conclude that H. amphikineta emerged from resting cysts. (ref. ID; 5727)

Type specimens

One slide of holotype specimens and three slides of paratype specimens (all protargol-impregnated) have been deposited in the collection of microscope slides of the Oberoserreichische Landesmuseum in Linz, Austria. Accession numbers: 86, 87, 88, 89/1989. (ref. ID; 5727)